Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Constraints on radiative forcing and future climate change from observations and climate model ensembles

Abstract

The assessment of uncertainties in global warming projections is often based on expert judgement, because a number of key variables in climate change are poorly quantified. In particular, the sensitivity of climate to changing greenhouse-gas concentrations in the atmosphere and the radiative forcing effects by aerosols are not well constrained, leading to large uncertainties in global warming simulations1. Here we present a Monte Carlo approach to produce probabilistic climate projections, using a climate model of reduced complexity. The uncertainties in the input parameters and in the model itself are taken into account, and past observations of oceanic and atmospheric warming are used to constrain the range of realistic model responses. We obtain a probability density function for the present-day total radiative forcing, giving 1.4 to 2.4 W m-2 for the 5–95 per cent confidence range, narrowing the global-mean indirect aerosol effect to the range of 0 to –1.2 W m-2. Ensemble simulations for two illustrative emission scenarios suggest a 40 per cent probability that global-mean surface temperature increase will exceed the range predicted by the Intergovernmental Panel on Climate Change (IPCC), but only a 5 per cent probability that warming will fall below that range.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Relation between radiative forcing, climate sensitivity, and modelled atmospheric and oceanic warming.
Figure 2: Constraints on the radiative forcing from the observed atmospheric and oceanic warming.
Figure 3: Probabilistic surface warming projections for two IPCC scenarios, as constrained by the observed atmospheric and oceanic warming.

References

  1. Houghton, J. T. et al. (eds) Climate Change 2001: The Scientific Basis (Cambridge Univ. Press, Cambridge, 2001).

    Google Scholar 

  2. Schneider, S. H. What is ‘dangerous’ in climate change? Nature 411, 17–19 (2001).

    ADS  CAS  Article  Google Scholar 

  3. Jones, P. D., New, M., Parker, D. E., Martin, S. & Rigor, I. G. Surface air temperature and its changes over the past 150 years. Rev. Geophys. 37, 173–199 (1999).

    ADS  Article  Google Scholar 

  4. Levitus, S., Antonov, J. I., Boyer, T. P. & Stephens, C. Warming of the world ocean. Science 287, 2225–2229 (2000).

    ADS  CAS  Article  Google Scholar 

  5. Santer, B. D. et al. A search for human influences on the thermal structure of the atmosphere. Nature 382, 39–46 (1996).

    ADS  CAS  Article  Google Scholar 

  6. Tett, S. F. B., Stott, P. A., Allen, M. R., Ingram, W. J. & Mitchell, J. F. B. Causes of twentieth-century temperature change near the Earth's surface. Nature 399, 569–572 (1999).

    ADS  CAS  Article  Google Scholar 

  7. Stott, P. A. et al. External control of 20th century temperature by natural and anthropogenic forcing. Science 290, 2133–2137 (2000).

    ADS  CAS  Article  Google Scholar 

  8. Hegerl, G. C. et al. Optimal detection and attribution of climate change: sensitivity of results to climate model differences. Clim. Dyn. 16, 737–754 (2000).

    Article  Google Scholar 

  9. Stott, P. A. et al. Attribution of twentieth century temperature change to natural and anthropogenic causes. Clim. Dyn. 17, 1–21 (2001).

    CAS  Article  Google Scholar 

  10. Barnett, T. R., Pierce, D. W. & Schnur, R. Detection of anthropogenic climate changes in the world's oceans. Science 292, 270–274 (2001).

    ADS  CAS  Article  Google Scholar 

  11. Allen, M. R., Stott, P. A., Mitchell, J. F. B., Schnur, R. & Delworth, T. L. Quantifying the uncertainty in forecasts of anthropogenic climate change. Nature 407, 617–620 (2000).

    ADS  CAS  Article  Google Scholar 

  12. Allen, M. R. et al. Quantifying anthropogenic influence on recent near-surface temperature change. Surv. Geophys. (in the press).

  13. Wigley, T. M. L. & Raper, S. C. B. Interpretation of high projections for global-mean warming. Science 293, 451–454 (2001).

    ADS  CAS  Article  Google Scholar 

  14. Hansen, J., Russell, G., Lacis, A., Fung, I. & Rind, D. Climate response times: Dependence on climate sensitivity and ocean mixing. Science 229, 857–859 (1985).

    ADS  CAS  Article  Google Scholar 

  15. Levitus, S. et al. Anthropogenic warming of Earth's climate system. Science 292, 267–270 (2001).

    ADS  CAS  Article  Google Scholar 

  16. Forest, C. E., Allen, M. R., Stone, P. H. & Sokolov, A. P. Constraining uncertainties in climate models using climate change detection techniques. Geophys. Res. Lett. 27, 469–572 (2000).

    Article  Google Scholar 

  17. Andronova, N. & Schlesinger, M. E. Objective estimation of the probability distribution for climate sensitivity. J. Geophys. Res. 106, 22605–22612 (2001).

    ADS  Article  Google Scholar 

  18. Gregory, J. M., Stouffer, R. J., Raper, S. C. B., Stott, P. A. & Rayner, N. A. An observationally based estimate of the climate sensitivity. J. Clim. (submitted).

  19. Forest, C. E., Stone, P. H., Sokolov, A. P., Allen, M. R. & Webster, M. D. Quantifying uncertainties in climate system properties with the use of recent climate observations. Science 295, 113–117 (2002).

    ADS  CAS  Article  Google Scholar 

  20. Nakićenović, N. et al. Special Report on Emission Scenarios (Intergovernmental Panel on Climate Change, Cambridge Univ. Press, 2000).

    Google Scholar 

  21. Stocker, T. F., Wright, D. G. & Mysak, L. A. A zonally averaged, coupled ocean-atmosphere model for paleoclimate studies. J. Clim. 5, 773–797 (1992).

    ADS  Article  Google Scholar 

  22. Schmittner, A. & Stocker, T. F. The stability of the thermohaline circulation in global warming experiments. J. Clim. 12, 1117–1133 (1999).

    ADS  Article  Google Scholar 

  23. Schmittner, A. & Stocker, T. F. A seasonally forced ocean-atmosphere model for paleoclimate studies. J. Clim. 14, 1055–1068 (2001).

    ADS  Article  Google Scholar 

  24. Plattner, G.-K., Joos, F., Stocker, T. F. & Marchal, O. Feedback mechanisms and sensitivities of ocean carbon uptake under global warming. Tellus B 53, 564–592 (2001).

    ADS  Google Scholar 

  25. Joos, F. et al. Global warming feedbacks on terrestrial carbon uptake under the IPCC emission scenarios. Glob. Biogeochem. Cycles 15, 891–907 (2001).

    ADS  CAS  Article  Google Scholar 

  26. Kattenberg, A. et al. in IPCC Second Scientific Assessment of Climate Change (eds Houghton, J. T. et al.) 285–357 (Cambridge Univ. Press, Cambridge, 1996).

    Google Scholar 

  27. Crowley, T. J. Causes of climate change over the past 1000 years. Science 289, 270–277 (2000).

    ADS  CAS  Article  Google Scholar 

  28. Boucher, O. & Haywood, J. On summing the components of radiative forcing of climate change. Clim. Dyn. 18, 297–302 (2001).

    Article  Google Scholar 

  29. Knutti, R., Stocker, T. F. & Wright, D. G. The effects of subgrid-scale parameterizations in a zonally averaged ocean model. J. Phys. Oceanogr. 30, 2738–2752 (2000).

    ADS  Article  Google Scholar 

Download references

Acknowledgements

We thank T. Crowley for providing the volcanic and solar radiative forcing data. This work was supported by the Swiss National Science Foundation.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Thomas F. Stocker.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Knutti, R., Stocker, T., Joos, F. et al. Constraints on radiative forcing and future climate change from observations and climate model ensembles. Nature 416, 719–723 (2002). https://doi.org/10.1038/416719a

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/416719a

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing